The field of the invention is laboratory apparatus, and the invention relates more specifically to devices for facilitating the microscopic or spectrophometric viewing of liquid specimens. Liquid specimens are typically viewed by placing a drop of the specimen on a transparent glass or plastic slide and covering the drop with a thin square cover slip. The cover slip spreads the liquid drop into a thin flat layer appropriate for viewing.
In certain microscopic evaluations, it is important to simplify and speed up the above-mentioned method, and this is especially true for repetitive tests such as carried out in hospital laboratories for blood or urine analysis. One particularly effective method is referred to under the trademark "kova" system which is described in applicant's U.S. Pat. No. 3,777,283. In the "Kova" system there described, a drop of the specimen is placed on a platform and drawn by capillary action into a chamber which spreads the liquid into a thin generally flat film appropriate for microscopic examination.
While the above described improved system has found wide-spread acceptance, it is nonetheless capable of further improvement. For instance, in the microscopic evaluation of a urine specimen, it is common practice to centrifuge a sample and to then draw a sample from the bottom of the centrifuged specimen which would be highly concentrated in any particulate matter and to then view this concentrated sample under a microscope. One technique for obtaining a sample from the bottom of a centrifuged specimen involves the use of a dropper with an elastic bulb on the top thereof which is inserted in the test tube so that the sample may be drawn from the bottom of the test tube. While the drop of such material may be readily placed on the platform, this does require a separate handling step which, in turn, gives rise to two potential sources of error or contamination namely, in the event that the dropper is contaminated, the reading would be in error and in the event the drop is placed in the wrong compartment, the sample would be reported incorrectly.
Thus, a method which reduces the handling of a centrifuged specimen and also reduces the possibility of unintentional interchanging of samples is needed. Furthermore, a method which eliminates the need for a separate dropper would not only reduce the possibility of cross-contamination but would also provide a less expensive analytical method.
Another test which is commonly run on samples of urine utilizes a plurality of reagent pads adhered to a single carrier strip. One such strip is sold under the trademark "Chemstrip" by Bio-Dynamics Division of Mannheim-Boehringer. Another strip is sold under the trademark "Multistix" by Ames Company, Division Miles Laboratories, Inc. In both instances, a plurality of reagent areas are placed on a single strip and the reagent areas are treated with different colormetric dyes which change color in the presence of various substances. For instance, one strip would provide a pH test, another would provide a protein test, a third, a glucose test, a fourth, a ketone test, a fifth, a bilirubin test, a sixth, a blood test, a seventh, a nitrite test and the eighth, a urobilinogen test. This colormetric test, while being a highly efficient method for running many tests at one time, has one disadvantage and that is the possibility of mislabling or interchanging of samples. A method which reduces the possibility of this error is needed.